Near-Infrared focal plane arrays (FPA's) are of considerable interest for numerous applications including astronomical imaging, spectroscopy, thermal imaging, night vision, eye-safe surveillance, food processing, etc. Of the many materials used for imaging systems that operate in the near infrared (e.g., HgCdTe, Ge, InSb, PtSi, etc.), InGaAs p-i-n detectors are most attractive for wavelengths between .lambda.=1 and 1.7 .mu.m due to their high performance and reliability [G. H. Olsen, "InGaAs fills the near-IR detector array vacuum," Laser Focus World, Vol. 27, pp. A21-A30, 1991]. The advantages of InGaAs p-i-n detectors include low dark current, high quantum efficiency, subnanosecond response, and room temperature operation. To date, 256.times.256 arrays of these detectors have been demonstrated for imaging purposes [G. Olsen, et al., "A 128.times.128 InGaAs detector array for 1.0-1.7 microns," in Proc. SPIE, Vol. 1341, 1990, pp. 432-437].
Most infrared imaging arrays demonstrated to date are hybrid devices, where the photodetectors are interconnected to silicon CMOS or CCD multiplexer readout arrays by either flip-chip or wire bonding. This not only degrades the performance of the arrays by introducing parasitics, but also significantly increases cost since multiple IC's are required, engendering complex manufacturing steps, and lowering yield due to the additional handling. Therefore, fully monolithic focal plane arrays which have the potential for reducing cost while increasing performance, are desirable.
Note that very low leakage current JFET arrays may also be used to fabricate liquid crystal backplanes for liquid crystal displays with extra-low power demand to hold the image between refresh cycles, which is particularly important in portable, battery operated equipment such as laptop computers.